Process of producing stable hydrocarbon oils



wreazsim' NI E STATES Him 1'. BROOKS, OI SOUN'D BEACH, OON'HEQIICU'I,ASSIGNOB TO THE GRAY- PATENT" .QFFICE comma-10x, or mm, m smear, acoaroaarron or minameme 0] PRODUCDIG STABLE HYDBOOAR'BON OILS IoDrawing.

This invention relates to the art ofoil reand more particularly to thetreatment rf light hydrocarbon oils having a tendency o discolor duringstorage and distribution mch as certain types of gasoline, or motorfuel, and kerosene, to improve the color stability thereof.

An object of this invention is to provide an mproved process of treatingsuch substances n a convenient, eflicient and economical manner.

A more specific object of this invention is 0 reduce substantiallycolorless light hydroasion oils having an improved stability as 0 colorand sedimentation so that they will emain colorless and clear,throughout an exended period of ex osure to sunlight, air and moderatelyelevategtemlperatures such as are ncountered commercial y during storageand listribution.

Qther objects of the invention will in part igtgbvious and will in partappear herein- L r. a I

The invention accordingly com rises the everal steps and the relation anorder of me or more of such steps with respect to each f the others, andthe product essing the Features, pro es, and the re ation ofcontituents,wh1ch are exemplified in the followng detailed disclosure,and the scope of the lfiplication of which will be indicated in the Thecommonly accepted uirements of good commercial grades of gaso 'ne andkerolene are that they shall not only be substanially colorless at thecom lotion of the rep but that ey shall remain :olor ess and earthroughout the somewhat axtended period of storage which usually enmesprior to their sale to the ultimate conrumer. this interval certain ofeven :he most care y refined oils have heretofore entlyl developeddiscoloratioili of a ct .owish, p e orange, or more rare y, p s:haracter, and this change has often been lccompanied by the developmentof a cloudy :pgearance and formation of a deposit or l'ment which isusually dark brown in :0 or.

Such discoloration and sedimentation se- Application filed October10,1985. Serial- No. 81,816.

riously depreciates the market value of such products, and in petroleumrefinery ractice, 1t is customary to test the refined gaso inc andkerosene for stability-by subjecting samples thereof in suitablereceptacles to the action of sunlight, air, and moderate heat wherebythe changes normally occurrin during storage are accelerated. The oils wich stand a test of exposure in colorless glass bottles to directsunlight for several days or of heating for several hours to about 212F., are considered to be of good quality, since experience has shownthat they usually do not become discolored durin storage.

This objectionable discoloration has been encountered more seriouslywith gasoline and kerosene manufactured by so-called crackmg processesthan with the similar oils obtained from crude tillation and whic arecommonly known as straight-run products, although it is well troleum byordinary disrecognized that gasolines and kerosenes which have beenrefined by any of the methods now in common use are likely to becomediscolored. Moreover since the causes of this color instability have notheretofore been understood, the attempts to overcome the difliculty havebeen varied in character and usually ineflicient and costly ofapplication. Examples of such attempts are the re-refining of such oilsby filtering through fullers earth, decolorlzlng charcoal and the likeor redistillation of the oil usually with the aid of steam.

Straight run lines and kerosenes are sometimes refine by'agitatin withan alkaline solution of sodium plum ite, acid treat ment being omitted.Gasolines treated in this we frequently become discolored, particular yif sulfur is added to the alkaline lumbite and gasoline mixture. In thecase 0 kerosene it is common practice to filter the refined kerosenethrough fullers earth, bauxite or other decolorizlng a nt to removecoloring matter. When freshly refined such gasohnes and kerosenes arecolorless and entirely free from traces of acid and alkali, bu. mayrap-- idl become discolored during stora ore frequently the practice ofg petroleum oils has included the well known steps of treatment withsulphuric acid, water,

alkali and sweetening agent and in the case of cracked gasolines thechemically treated gasoline or pressure distillate is redistilled. t ispossible withproper crackingand rectifying apxparatus, to roduce apressure distlllate w ch has a 150' 'ng point range of ordinarygasoline, the chief objection to such practice has been the nty ofredist' standing-or in the sunl' t or heating tee It has alsobeen founythatorganic nit1 gen bases or derivatives of annnonia,, whi are erallymore soluble in h drocarb oils an gaseous ammonia, are efiecti 1np'reventm discoloration. Of these game bases, 1t 1s, eferred to employtlu 111mg which do not readily form colored oxidati these oils afterrefining color-table product.

By the present invention, it'has been found that the discoloration ofhydrocarbon oils ha a tendency to discolor during storage and ribution,such as certain addition -of certain e or basic substances to freshlyprepared neutral oils as roduced by the customary refimf methods.-thaslongbeenrecognised,in erefining 2o olfapetroleum oils, that alltraces of free mine acids, such as sulphuric acid or sulphuric dioxide,used in the refining rocess, should be .thorou hly removed by e abovementioned w with water and neutralization as with alka'lies prior to thefinal distillation of the oil; the prewnt invention is to beparticularly distinguished from such old ractice.

-Intheimprovedprocessofo a color-stable .roduct, comprisin the presentso invention, it been found desirable to com- 10 with the freshlprepared refined oil an line or basic su ce which will remain in therefined oil during storage and will efiectivelyneutralize or overcomeeither 85 an slight traces of acid which might be initi y presenttherein after the last distlllation and more particularly the acidswhich I find develop or tend to develop therein during such stora itbeing preferred, however, to 40 add the 'ne substance in amounts suchthat at the end of the storage period there is substantially no freeexcess of the e agent. This discoloration is due rhaps to the presencein the refined oil 0 inorganic 4s substances, such as free sulphur, orof organic substances of'a more or less complex nature, which may yieldacids by slow decomposition, oxidation or hydrolysis.

Althou h in the accomplishment of this re- 60 sult, alkaline substancesof-a relatively oilinsoluble nature such asllligdratedlime, calciumcarbonate and the e mi ht be used, it has been found to be preferab e touse oilsoluble bases such as ammonia or certain of 55 its alkalinecompounds or derivatives. A1-- thou h ammonia is nerally considered tobe inso uble in miner oils, it has been found that it is suflicientlysoluble in light hydrocarbon oils to have the efiect of preventingdiscoloration and that, although gasoline is capable of taking up ordissolving about 3 grams of anhydrous ammonia per gallon, at 20 C.,usually 0.5 grams more or less of ammonia (NI-1,), per gallon issuflicient to revent discoloration or sedimentation on ong in order toobtain a,

' m1ne, trimethyl amine,

15 and kerosenes, is efiectivel prevented by the oils and that by theuse of' the cases to simplify or curtail or condensation products suchas benzyi ethylamine, pop I mine and the aliphatic p secon a andtertiary amines generally. t has herel fore been suggested to add'amiline or 0th aromatic aunnes to a refined h drocarbon order to reducemotor knock and to eiln nate the deposition of carbon in the comb\ tionchamber. Since these latter substam tend readily to form coloredoxidation a: condensation products they are not suital for use toaccomplish the purpose of the pn ent invention, and by the-use of theterm 0 or-stable in the present claims it is intend to exclude suchsubstances. 7 a

It has been found that the present inve tion may be successfully ap liedto light 11 drocarbon oils such as e and kerose having a tendency todiscolor dur' store and distribution, even when refined any the methodsnow employed in refining su principlesthe present invention it is le inmm A e series of o ations heretofore considered-n ry. example',- it hasbeen found in the case of t' refinmggf cracked oils, that the finaldistill tion a r the sulphuric acid, water,.alka and sweeteningtreatment need not be ca ried.out if a basic substance is added to t?rgfined and, neutralized oils,"as describ a ve. a

The following" examplesillustrate the ma ner and eflectiveness o theapplication of t] resent invention to various types of gas One-half onof crude cracked gasolil was refined agitating with concentrau sulphuricaci in the roportions, of fi pounds of acid per 42 one of oil, the acandtar separated, the oil washed with wet and an excess of caustic sodaand then swee ened by agtating with sodium lumbi solution. 0 gasolinethus refin was d vided into two portions, to one of which an monia wasadded in thelgroportions of abol 1.5 grams per gallon. th the neutralp0: tion and the portion containing ammom' were then explosed to directsunlight. Whi the color of t e original, refined gasoline we 23 on theSaybolt color scale, the portio treated with ammonia retained this colcafter two days exposure to sunlight, the ne1 tralized oil containing noammonia darl ened in color in three hours to about 15 o the Sayboltscale, and at the end of the tw days had become too dark to measure onth iybolt scale and had formed a nearly black :posit of insolublematter. 7

A straight run gasoline, distilled from a 'ude petroleum, was refined bysweetening 11y, acid treatment being omitted, as is often 1e practicewith gasolines of this type. :alf a gallon of this gasoline wassweetened alkaline plumbite solution and a portion E the oil so refinedwas treated with am- ,onia in the proportion of .6 gram per gal- In;both portions were then exposed three ays to direct sunlight, at .theend of which me the portion treated with ammonia lowed a color of on theSaybolt scale, 1e same as the original color, and the poron containingno ammonia had become yelw in color equivalent to about 17 on the ayboltscale.

One half gallon of straight run gasoline as agitated with dilute calciumhypochloite solution until sweet to the alkaline plumite reaction. Theproduct so treated was ivided into two portions, one of which was 'eatedwith ammonia in the proportions of .5 gram NH per gallon of oil, and nofurier treatment was given the other portion. ioth samples showed 25+color on the Sayolt scale but after two days exposure to irect sunlightthe one containin ammonia amained colorless but the one without amloniahad become yellow in color to the exant of about 19 on the Sayboltscale.

In practicing the invention on an indusrial scale, it has been found tobe convenient prepare gaseous ammonia by adding conentrated aqueousammonia to solid caustic lkali such as caustic soda, whereby nearly ryammonia gas is evolved; quickhme may e used in the same way, but theammonia not so dry. The oil may be agitated with oncentrated aqueousammonia and the aqueus layer, still containing most of the amionia, thenseparated, but this is of course, wasteful of ammonia. A preferredproce- .ure, adapted to treating large volumes of il, 1s to releasegaseous ammonia from a ylinder of anhydrous ammonia, by means f asuitable reducing valve, and pass the mmonia gas at a controlled rateinto the oil. The gas may be passed continuously into a tream of the oilas it passes to storage, or a ar e tank of refined gasoline may betreated iy ubbling the gas into the oil near the botom.

When a liquid base such as trimethyl amine s employed, it is necessarymerely to add a measured quantity of the base to a definite plume of theoil in any way providing for )roper mixing of the liquids. As withamnonia, the quantities required will depend omewhat upon the purity ofthe oil and upon ts tendency to discolor but the amounts necessary toeffect color-stability are within he range 0.5 to 5 grams per gallon formost IXJIDPIBS of such oils; a very badly refined oil or oneexceptionally rich in impurities, may require a somewhat larger amount.

Since certain changes in carr ing out the above process, and certain moifications in the composition which embody the invention may be madewithout departing from its scope, it is intended that all mattercontained in the above description shall be interpreted as illustrativeand not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebe tween.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

. 1. A process for stabilizing the color of gasoline which comprisestreating a freshly prepared and chemically refined gasoline with ammoniain an amount from about 0.5 grams to about 1.5 grams ammonia per gallonof gasoline treated.

2. A process for stabilizing the color of gasoline which comprisestreating a freshly prepared and chemically refined gasoline with ammoniain an amount of about 0.5 grams ammonia per gallon of gasoline treated.

In testimony whereof I atfix my signature.

BENJAMIN T. BROOKS.

